feat(ui-lvgl): European fonts and phone-style keyboard

Fonts: Noto Sans generated with lv_font_conv (ui-lvgl/fonts/generate.sh,
OFL) replaces ASCII-only Montserrat: European Latin (Latin-1, Extended-A/B),
Greek, Cyrillic + supplement, typographic punctuation, currency, LVGL
symbols + globe; 12/14/16/20 px, clock 40 px digits only (RLE, so
LV_USE_FONT_COMPRESSED is on).

Keyboard (ui-lvgl/Keyboard.h): one layout per script (Latin QWERTY,
Cyrillic, Greek) picked by the same keyboard_main/alt_alphabet prefs as
ui-new, globe key to switch, hold a key for its variants in a popup above
it, one-shot shift, symbols page; compose limit counted in UTF-8 bytes.
First Settings screen (Keyboard: Main / Additional).

Long-press variants and UTF-8 case mapping move to ui-core/KeyboardData.h
and are shared with ui-new, whose Hold-Enter accents gain Romanian,
Turkish, Hungarian, Baltic and Icelandic letters (and ș/ț, Ukrainian /
Serbian letters now capitalise).

Verified on L2 hardware.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

solo/wio-tracker-l2/platformio.ini

@@ -60,6 +60,7 @@ build_src_filter = ${Wio_Tracker_L2.build_src_filter}
   +<helpers/ui/MomentaryButton.cpp>
   +<../examples/companion_radio/*.cpp>
   +<../examples/companion_radio/ui-lvgl/*.cpp>
+  +<../examples/companion_radio/ui-lvgl/fonts/*.c>
 lib_deps =
   ${Wio_Tracker_L2.lib_deps}
   densaugeo/base64 @ ~1.4.0